The long term objectives of the research proposed is to understand the molecular and cellular basis for the development of the cerebral cortex. The specific hypothesis we aim to investigate is that the embryonic cerebral cortex-restricted transcription factors Emx1 and/or Emx2 regulate the transcription of target genes with limits of expression demarcating the developing cerebral cortex. The approach taken is to determine endogenous expression levels of Emx1 and Emx2 in various murine neural cell lines, including several derived from the cortex, using Northern blots. Choosing a cell line with little endogenous Emx expression, an inducible Emx1 and/or Emx2 gene will be stably integrated using a calcium phosphate transfection protocol. The Emx genes will be highly expressed after removal of low levels of tetracycline from the cell culture medium. mRNA transcripts that are up- or downregulated after Einx induction will be identified using RDA and PCR differential display. Subtraction products will be screened for embryonic cerebral cortex expression using in situ hybridization, and the most interesting of these will be characterized by DNA sequencing. Understanding the molecular interactions responsible for normal development of the cerebral cortex could shed light on the multitude of characterized problems with this organ, ranging from dyslexia to schizophrenia.